Jump to content

baggage pods


dust

Recommended Posts

OK so I'm putting pods on, can I give them a "porpoise" shape to reduce drag. I only have to glue up 26 2x4's to turn 48" x 16" body on my lathe, think I'll stand to the side when i turn it on

maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

Link to comment
Share on other sites

Mike Arnolds AR-5 mentions "It has been found (3) that Navy torpedoes with a flat face of half the body diameter, faired elliptically into the forebody, had the same drag as a streamlined body (of the same wetted area)."

 

(3) Phone call by writer to engineers at Naval Ordnance Test Station, Pasadena 1962

 

dust asked me what "faired elliptically" means. I dont know. But here is a pic of this data in use.

 

Anyone got a line on the original data?

post-296-141090151711_thumb.jpg

Link to comment
Share on other sites

My friend Dr. Kevin Funk built a set of baggage pods for his Cozy and uses them when flying the family. Capacity of each one is about the size of a very small duffle and his saddle mount to the strake is strong enough to support his weight when standing on it. He states that he has no appreciable drag with them installed.

 

He modeled them after some long-EZ pods he saw at OSH. He made up some molds and laid the pods up for himself and for another builder. Drop him a line at COZYMK4@aol.com

Terry Winnett, Capt, USAF

Cozy MkIV #792

RAF Lakenheath, U.K.

Link to comment
Share on other sites

Largeprime,

 

The flat areas in the picture you attached of the mk 80 series bombs actually have nothing to do with aerodynamics but are the nose fuzewell. When they are on the aircraft there is either an external fuse that sticks out the nose, an internal fuze, or the fuzewell is left empty (only if a tail fuze is used or if it is concrete filled). In the case of the last two there are a variety of nose plugs that fit on the nose to provide an aerodynamic shape. Although the aerodynamic nose plug is a pretty blunt cone and does not follow the overall shape of the bomb, it is not flat. Here is an example:

 

External fuze

 

Nose plug

 

As far as torpedoes go, my Navy brethren would know more about them than I. I’ve seen several up close, but I was more concerned with the payload than the shape.

 

There are several projectiles that have a blunt nose, but the shape has been engineered for armor penetration instead of aerodynamic efficiency. In fact, many projectiles that are made for penetration use a "ballistic windshield" made of light aluminum that covers the flat nose of the projectile to increase stability and range.

 

Not to say that what you are saying about blunt nose aerodynamics is not true though. I think it definitely deserves more study.

 

Jake

Link to comment
Share on other sites

I plan on attatching my baggage pods in a more permanant fashion than what I have seen at the fly-ins. At the front of each pod I will have a 1MCP landing light with hideaway strobes installed in the reflectors for recognition lights, or maybe lower wattage bulbs instead of the strobes. I am willing to give up a couple mph for the cool looks, added storage, and landinglight location and convienance.

I will definatly need the extra storage as I will also be enlarging the fuel capacity by using up some of the strake storage space for fuel tank.

Dave Clifford

"The Metal Man" Musketeer

Vise grip hands and Micrometer eyes!!

 

Cozy MKIV Plans #656

Link to comment
Share on other sites

  • 1 year later...

Dust,

 

You're in the right direction with the porpose (porpous, pourpus?), dolphin look although I'd go more for the shark look for streamlining. It's a bit of a crap shoot. A tradeoff of one thing for another. Like airplane wings. I talked to a few guys at Rough River about it and the common thought is that the pods give a bit more ground effect lift at takeoff. Otherwise I got a "no difference" or "about 1 or 2 knots slower". The fatter and more blunt nose pod, the more turbulent effect. But wider is more room. Just make them strong enough so they'll help when you forget to put down your landing gear.

Link to comment
Share on other sites

  • 7 months later...

I have been trying to figure out the placement of the baggage pods and how are they fastened to the wing? Would anyone like to share how they designed their pods?

Erick

You could just make a j-hook that hooked over the leading edge, and a hard point mounted drilled and tapped piece of stock. When you bolted the pod to the hard point, the j-hook would hold the front up.

 

If you want a pic, I can whip up something and post it.

Link to comment
Share on other sites

OK so, does anyone know where i go to find out how to design an effecient, low drag porpoise pod?

You may find some interesting discussion and links on this page.

 

http://www.wisil.recumbents.com/wisil/barracuda/barracudafairingdesign.htm

 

There is a link to some aerodynamic applets that let you play with shapes and watch the impact on drag and such.

 

He also has some interesting information about blowing plastic bubbles (canopies) which could be applicable. Cut your template, blow the left side, flip it over, blow the right side. Use these for molds for your glass layup.

 

-Norm

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information